Toyota Motor Corp. and Nippon Telegraph and Telephone Corp. are to cooperate on high-speed communication technology needed to commercialize "connected cars," sources close to the matter said Thursday. Toyota and NTT will jointly study the use of next-generation 5G technology to enable autonomous cars to gather various types of information on traffic conditions and exchange data between self-driving vehicles to ensure their smooth and safe operation. Toyota has already developed a communication system for cars which can be used to monitor traffic to avoid congested roads and help drivers navigate during natural disasters. The automaker has tied-up with KDDI Corp., a major Japanese mobile communication carrier, to develop a global platform for connected cars, aiming to equip all of its vehicles sold in Japan and the United States with a device to access the network by 2020. Honda Motor Co. and SoftBank Group Corp. are seeking to jointly develop an artificial intelligence-based system for cars that can interact with drivers.